windows: fix callStateChanged handling

Refs #72789

Change-Id: I2d99c0544513a885d05530247681587211059c10
diff --git a/callwidget.cpp b/callwidget.cpp
index fefa346..100fa4a 100644
--- a/callwidget.cpp
+++ b/callwidget.cpp
@@ -194,13 +194,15 @@
 CallWidget::callStateChanged(Call* call, Call::State previousState)
 {
     Q_UNUSED(previousState)
+    if (call == nullptr)
+        return;
     ui->callList->setCurrentIndex(callModel_->getIndex(actualCall_));
     if (call->state() == Call::State::OVER) {
         actualCall_ = nullptr;
         ui->videoWidget->hide();
     } else if (call->state() == Call::State::HOLD) {
         ui->videoWidget->hide();
-    } else {
+    } else if (call->state() == Call::State::CURRENT){
         ui->videoWidget->show();
         ui->messageOutput->setModel(
                     IMConversationManager::instance()->getModel(actualCall_));